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Conserva MR, Redavid I, Anelli L, Zagaria A, Tarantini F, Cumbo C, Tota G, Parciante E, Coccaro N, Minervini CF, Minervini A, Specchia G, Musto P, Albano F. IKAROS in Acute Leukemia: A Positive Influencer or a Mean Hater? Int J Mol Sci 2023; 24:ijms24043282. [PMID: 36834692 PMCID: PMC9961161 DOI: 10.3390/ijms24043282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/31/2023] [Accepted: 02/04/2023] [Indexed: 02/11/2023] Open
Abstract
One key process that controls leukemogenesis is the regulation of oncogenic gene expression by transcription factors acting as tumor suppressors. Understanding this intricate mechanism is crucial to elucidating leukemia pathophysiology and discovering new targeted treatments. In this review, we make a brief overview of the physiological role of IKAROS and the molecular pathway that contributes to acute leukemia pathogenesis through IKZF1 gene lesions. IKAROS is a zinc finger transcription factor of the Krüppel family that acts as the main character during hematopoiesis and leukemogenesis. It can activate or repress tumor suppressors or oncogenes, regulating the survival and proliferation of leukemic cells. More than 70% of Ph+ and Ph-like cases of acute lymphoblastic leukemia exhibit IKZF1 gene variants, which are linked to worse treatment outcomes in both childhood and adult B-cell precursor acute lymphoblastic leukemia. In the last few years, much evidence supporting IKAROS involvement in myeloid differentiation has been reported, suggesting that loss of IKZF1 might also be a determinant of oncogenesis in acute myeloid leukemia. Considering the complicated "social" network that IKAROS manages in hematopoietic cells, we aim to focus on its involvement and the numerous alterations of molecular pathways it can support in acute leukemias.
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Affiliation(s)
- Maria Rosa Conserva
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Immacolata Redavid
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Luisa Anelli
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Antonella Zagaria
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Francesco Tarantini
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Cosimo Cumbo
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Giuseppina Tota
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Elisa Parciante
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Nicoletta Coccaro
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Crescenzio Francesco Minervini
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Angela Minervini
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Giorgina Specchia
- School of Medicine, University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Pellegrino Musto
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
| | - Francesco Albano
- Hematology Section, Department of Precision and Regenerative Medicine and Ionian Area (DiMePRe-J), University of Bari ‘Aldo Moro’, 70124 Bari, Italy
- Correspondence:
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2
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Micklethwaite KP, Gowrishankar K, Gloss BS, Li Z, Street JA, Moezzi L, Mach MA, Sutrave G, Clancy LE, Bishop DC, Louie RHY, Cai C, Foox J, MacKay M, Sedlazeck FJ, Blombery P, Mason CE, Luciani F, Gottlieb DJ, Blyth E. Investigation of product-derived lymphoma following infusion of piggyBac-modified CD19 chimeric antigen receptor T cells. Blood 2021; 138:1391-1405. [PMID: 33974080 PMCID: PMC8532197 DOI: 10.1182/blood.2021010858] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/24/2021] [Indexed: 11/20/2022] Open
Abstract
We performed a phase 1 clinical trial to evaluate outcomes in patients receiving donor-derived CD19-specific chimeric antigen receptor (CAR) T cells for B-cell malignancy that relapsed or persisted after matched related allogeneic hemopoietic stem cell transplant. To overcome the cost and transgene-capacity limitations of traditional viral vectors, CAR T cells were produced using the piggyBac transposon system of genetic modification. Following CAR T-cell infusion, 1 patient developed a gradually enlarging retroperitoneal tumor due to a CAR-expressing CD4+ T-cell lymphoma. Screening of other patients led to the detection, in an asymptomatic patient, of a second CAR T-cell tumor in thoracic para-aortic lymph nodes. Analysis of the first lymphoma showed a high transgene copy number, but no insertion into typical oncogenes. There were also structural changes such as altered genomic copy number and point mutations unrelated to the insertion sites. Transcriptome analysis showed transgene promoter-driven upregulation of transcription of surrounding regions despite insulator sequences surrounding the transgene. However, marked global changes in transcription predominantly correlated with gene copy number rather than insertion sites. In both patients, the CAR T-cell-derived lymphoma progressed and 1 patient died. We describe the first 2 cases of malignant lymphoma derived from CAR gene-modified T cells. Although CAR T cells have an enviable record of safety to date, our results emphasize the need for caution and regular follow-up of CAR T recipients, especially when novel methods of gene transfer are used to create genetically modified immune therapies. This trial was registered at www.anzctr.org.au as ACTRN12617001579381.
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MESH Headings
- Aged
- DNA Transposable Elements
- Gene Expression Regulation, Neoplastic
- Gene Transfer Techniques
- Humans
- Immunotherapy, Adoptive/adverse effects
- Immunotherapy, Adoptive/methods
- Leukemia, B-Cell/genetics
- Leukemia, B-Cell/therapy
- Lymphoma/etiology
- Lymphoma/genetics
- Lymphoma, B-Cell/genetics
- Lymphoma, B-Cell/therapy
- Male
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/therapeutic use
- T-Lymphocytes/metabolism
- Transcriptome
- Transgenes
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Affiliation(s)
- Kenneth P Micklethwaite
- Blood Transplant and Cell Therapies Program, Department of Haematology, Westmead Hospital, Sydney, NSW, Australia
- Blood Transplant and Cell Therapies Laboratory, NSW Health Pathology-ICPMR Westmead, Sydney, NSW, Australia
- Sydney Medical School, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Kavitha Gowrishankar
- Westmead Institute for Medical Research, Sydney, NSW, Australia
- Sydney Medical School, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Brian S Gloss
- Westmead Institute for Medical Research, Sydney, NSW, Australia
- Sydney Medical School, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Ziduo Li
- Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Janine A Street
- Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Leili Moezzi
- Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - Melanie A Mach
- Westmead Institute for Medical Research, Sydney, NSW, Australia
- Sydney Medical School, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Gaurav Sutrave
- Blood Transplant and Cell Therapies Program, Department of Haematology, Westmead Hospital, Sydney, NSW, Australia
- Westmead Institute for Medical Research, Sydney, NSW, Australia
- Sydney Medical School, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Leighton E Clancy
- Blood Transplant and Cell Therapies Laboratory, NSW Health Pathology-ICPMR Westmead, Sydney, NSW, Australia
- Westmead Institute for Medical Research, Sydney, NSW, Australia
| | - David C Bishop
- Blood Transplant and Cell Therapies Program, Department of Haematology, Westmead Hospital, Sydney, NSW, Australia
- Westmead Institute for Medical Research, Sydney, NSW, Australia
- Sydney Medical School, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Raymond H Y Louie
- Kirby Institute, University of New South Wales, Sydney. NSW, Australia
| | - Curtis Cai
- Kirby Institute, University of New South Wales, Sydney. NSW, Australia
| | - Jonathan Foox
- Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY
- The Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, New York, NY
| | - Matthew MacKay
- Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY
- The Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, New York, NY
| | - Fritz J Sedlazeck
- Human Genome Sequencing Center, College of Medicine, Baylor University, Houston, TX
| | - Piers Blombery
- Department of Pathology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
- Clinical Haematology, The Royal Melbourne Hospital and Peter MacCallum Cancer Centre, Parkville, VIC, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia
| | - Christopher E Mason
- Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY
- The Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, New York, NY
- The Feil Family Brain and Mind Research Institute, New York, NY; and
- The WorldQuant Initiative for Quantitative Prediction, New York, NY
| | - Fabio Luciani
- Kirby Institute, University of New South Wales, Sydney. NSW, Australia
| | - David J Gottlieb
- Blood Transplant and Cell Therapies Program, Department of Haematology, Westmead Hospital, Sydney, NSW, Australia
- Westmead Institute for Medical Research, Sydney, NSW, Australia
- Sydney Medical School, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Emily Blyth
- Blood Transplant and Cell Therapies Program, Department of Haematology, Westmead Hospital, Sydney, NSW, Australia
- Blood Transplant and Cell Therapies Laboratory, NSW Health Pathology-ICPMR Westmead, Sydney, NSW, Australia
- Westmead Institute for Medical Research, Sydney, NSW, Australia
- Sydney Medical School, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
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3
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Dawes JC, Uren AG. Forward and Reverse Genetics of B Cell Malignancies: From Insertional Mutagenesis to CRISPR-Cas. Front Immunol 2021; 12:670280. [PMID: 34484175 PMCID: PMC8414522 DOI: 10.3389/fimmu.2021.670280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 07/09/2021] [Indexed: 12/21/2022] Open
Abstract
Cancer genome sequencing has identified dozens of mutations with a putative role in lymphomagenesis and leukemogenesis. Validation of driver mutations responsible for B cell neoplasms is complicated by the volume of mutations worthy of investigation and by the complex ways that multiple mutations arising from different stages of B cell development can cooperate. Forward and reverse genetic strategies in mice can provide complementary validation of human driver genes and in some cases comparative genomics of these models with human tumors has directed the identification of new drivers in human malignancies. We review a collection of forward genetic screens performed using insertional mutagenesis, chemical mutagenesis and exome sequencing and discuss how the high coverage of subclonal mutations in insertional mutagenesis screens can identify cooperating mutations at rates not possible using human tumor genomes. We also compare a set of independently conducted screens from Pax5 mutant mice that converge upon a common set of mutations observed in human acute lymphoblastic leukemia (ALL). We also discuss reverse genetic models and screens that use CRISPR-Cas, ORFs and shRNAs to provide high throughput in vivo proof of oncogenic function, with an emphasis on models using adoptive transfer of ex vivo cultured cells. Finally, we summarize mouse models that offer temporal regulation of candidate genes in an in vivo setting to demonstrate the potential of their encoded proteins as therapeutic targets.
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Affiliation(s)
- Joanna C Dawes
- Medical Research Council, London Institute of Medical Sciences, London, United Kingdom.,Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Anthony G Uren
- Medical Research Council, London Institute of Medical Sciences, London, United Kingdom.,Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, United Kingdom
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4
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Transcriptional Regulation of Genes by Ikaros Tumor Suppressor in Acute Lymphoblastic Leukemia. Int J Mol Sci 2020; 21:ijms21041377. [PMID: 32085659 PMCID: PMC7073093 DOI: 10.3390/ijms21041377] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/13/2020] [Accepted: 02/14/2020] [Indexed: 12/27/2022] Open
Abstract
Regulation of oncogenic gene expression by transcription factors that function as tumor suppressors is one of the major mechanisms that regulate leukemogenesis. Understanding this complex process is essential for explaining the pathogenesis of leukemia as well as developing targeted therapies. Here, we provide an overview of the role of Ikaros tumor suppressor and its role in regulation of gene transcription in acute leukemia. Ikaros (IKZF1) is a DNA-binding protein that functions as a master regulator of hematopoiesis and the immune system, as well as a tumor suppressor in acute lymphoblastic leukemia (ALL). Genetic alteration or functional inactivation of Ikaros results in the development of high-risk leukemia. Ikaros binds to the specific consensus binding motif at upstream regulatory elements of its target genes, recruits chromatin-remodeling complexes and activates or represses transcription via chromatin remodeling. Over the last twenty years, a large number of Ikaros target genes have been identified, and the role of Ikaros in the regulation of their expression provided insight into the mechanisms of Ikaros tumor suppressor function in leukemia. Here we summarize the role of Ikaros in the regulation of the expression of the genes whose function is critical for cellular proliferation, development, and progression of acute lymphoblastic leukemia.
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5
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Insertional mutagenesis using the Sleeping Beauty transposon system identifies drivers of erythroleukemia in mice. Sci Rep 2019; 9:5488. [PMID: 30940846 PMCID: PMC6445099 DOI: 10.1038/s41598-019-41805-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 03/19/2019] [Indexed: 12/26/2022] Open
Abstract
Insertional mutagenesis is a powerful means of identifying cancer drivers in animal models. We used the Sleeping Beauty (SB) transposon/transposase system to identify activated oncogenes in hematologic cancers in wild-type mice and mice that express a stabilized cyclin E protein (termed cyclin ET74AT393A). Cyclin E governs cell division and is misregulated in human cancers. Cyclin ET74AT393A mice develop ineffective erythropoiesis that resembles early-stage human myelodysplastic syndrome, and we sought to identify oncogenes that might cooperate with cyclin E hyperactivity in leukemogenesis. SB activation in hematopoietic precursors caused T-cell leukemia/lymphomas (T-ALL) and pure red blood cell erythroleukemias (EL). Analysis of >12,000 SB integration sites revealed markedly different oncogene activations in EL and T-ALL: Notch1 and Ikaros were most common in T-ALL, whereas ETS transcription factors (Erg and Ets1) were targeted in most ELs. Cyclin E status did not impact leukemogenesis or oncogene activations. Whereas most SB insertions were lost during culture of EL cell lines, Erg insertions were retained, indicating Erg's key role in these neoplasms. Surprisingly, cyclin ET74AT393A conferred growth factor independence and altered Erg-dependent differentiation in EL cell lines. These studies provide new molecular insights into erythroid leukemia and suggest potential therapeutic targets for human leukemia.
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6
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Ge Z, Zhou X, Gu Y, Han Q, Li J, Chen B, Ge Q, Dovat E, Payne JL, Sun T, Song C, Dovat S. Ikaros regulation of the BCL6/BACH2 axis and its clinical relevance in acute lymphoblastic leukemia. Oncotarget 2018; 8:8022-8034. [PMID: 28030830 PMCID: PMC5352379 DOI: 10.18632/oncotarget.14038] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 11/24/2016] [Indexed: 12/27/2022] Open
Abstract
B-Cell CLL/Lymphoma 6 (BCL6) is a proto-oncogene that is highly expressed in acute lymphoblastic leukemia (ALL). BTB and CNC Homology 1 Basic Leucine Zipper Transcription Factor 2 (BACH2) is a suppressor of transcription. The BACH2-BCL6 balance controls selection at the pre-B cell receptor checkpoint by regulating p53 expression. However, the underlying mechanism and the clinical relevance of the BCL6/BACH2 axis are unknown. Here, we found that Ikaros, a tumor suppressor encoded by IKZF1, directly binds to both the BCL6 and BACH2 promoters where it suppresses BCL6 and promotes BACH2 expression in B-cell ALL (B-ALL) cells. Casein kinase 2 (CK2) inhibitors increase Ikaros function thereby inhibiting BCL6 and promoting BACH2 expression in an Ikaros-dependent manner. We also found that the expression of BCL6 is higher while BACH2 expression is lower in patients with B-ALL than normal bone marrow control. High BCL6 and low BACH2 expression is associated with high leukemic cell proliferation, unfavorable clinical and laboratory features, and inferior outcomes. Moreover, IKZF1 deletion is associated with high BCL6 and low BACH2 expression in B-ALL patients. CK2 inhibitors increase Ikaros binding to the promoter of BCL6 and BACH2 and suppress BCL6 while promoting BACH2 expression in the primary B-ALL cells. Our data indicates that Ikaros regulates expression of the BCL6/BACH2 axis in B-ALL. High BCL6 and low BACH2 expression are associated with Ikaros dysregulation and have a potential effect on the development of B-ALL.
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Affiliation(s)
- Zheng Ge
- Department of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China.,International Cooperative Leukemia Group and International Cooperative Laboratory of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China
| | - Xilian Zhou
- Department of Hematology, The First Affiliated Hospital of Nanjing Medical University, Jiangsu Province Hospital, Nanjing 210029, China
| | - Yan Gu
- Department of Hematology, The First Affiliated Hospital of Nanjing Medical University, Jiangsu Province Hospital, Nanjing 210029, China
| | - Qi Han
- Department of Hematology, The First Affiliated Hospital of Nanjing Medical University, Jiangsu Province Hospital, Nanjing 210029, China
| | - Jianyong Li
- Department of Hematology, The First Affiliated Hospital of Nanjing Medical University, Jiangsu Province Hospital, Nanjing 210029, China
| | - Baoan Chen
- Department of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China.,International Cooperative Leukemia Group and International Cooperative Laboratory of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China
| | - Qinyu Ge
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Elanora Dovat
- Department of Pediatrics, Pennsylvania State University Medical College, Hershey, PA 17033, USA
| | - Jonathon L Payne
- Department of Pediatrics, Pennsylvania State University Medical College, Hershey, PA 17033, USA.,Loma Linda University School of Medicine, Department of Basic Sciences, Loma Linda, CA 92350, USA
| | - Tianyu Sun
- Department of Internal Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Chunhua Song
- International Cooperative Leukemia Group and International Cooperative Laboratory of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China.,Department of Pediatrics, Pennsylvania State University Medical College, Hershey, PA 17033, USA
| | - Sinisa Dovat
- International Cooperative Leukemia Group and International Cooperative Laboratory of Hematology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China.,Department of Pediatrics, Pennsylvania State University Medical College, Hershey, PA 17033, USA
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7
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Abstract
Advances in technology have made it possible to analyze integration sites in cells from HIV-infected patients. A significant fraction of infected cells in patients on long-term therapy are clonally expanded; in some cases the integrated viral DNA contributes to the clonal expansion of the infected cells. Although the large majority (>95%) of the HIV proviruses in treated patients are defective, expanded clones can carry replication-competent proviruses, and cells from these clones can release infectious virus. As discussed in this Perspective, it is likely that cells that produce virus are strongly selected against in vivo, and cells with replication competent proviruses expand and survive because only a small fraction of the cells produce virus. These findings have implications for strategies that are intended to eliminate the reservoir of infected cells that has made it almost impossible to cure HIV-infected patients.
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Affiliation(s)
- Stephen H Hughes
- HIV Drug Resistance Program, National Cancer Institute, Frederick, MD 21702, USA.
| | - John M Coffin
- Department of Molecular Biology and Microbiology, Tufts University, Boston, MA 02111, USA
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8
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Cesana D, Santoni de Sio FR, Rudilosso L, Gallina P, Calabria A, Beretta S, Merelli I, Bruzzesi E, Passerini L, Nozza S, Vicenzi E, Poli G, Gregori S, Tambussi G, Montini E. HIV-1-mediated insertional activation of STAT5B and BACH2 trigger viral reservoir in T regulatory cells. Nat Commun 2017; 8:498. [PMID: 28887441 PMCID: PMC5591266 DOI: 10.1038/s41467-017-00609-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 07/12/2017] [Indexed: 12/13/2022] Open
Abstract
HIV-1 insertions targeting BACH2 or MLK2 are enriched and persist for decades in hematopoietic cells from patients under combination antiretroviral therapy. However, it is unclear how these insertions provide such selective advantage to infected cell clones. Here, we show that in 30/87 (34%) patients under combination antiretroviral therapy, BACH2, and STAT5B are activated by insertions triggering the formation of mRNAs that contain viral sequences fused by splicing to their first protein-coding exon. These chimeric mRNAs, predicted to express full-length proteins, are enriched in T regulatory and T central memory cells, but not in other T lymphocyte subsets or monocytes. Overexpression of BACH2 or STAT5B in primary T regulatory cells increases their proliferation and survival without compromising their function. Hence, we provide evidence that HIV-1-mediated insertional activation of BACH2 and STAT5B favor the persistence of a viral reservoir in T regulatory cells in patients under combination antiretroviral therapy. HIV insertions in hematopoietic cells are enriched in BACH2 or MLK2 genes, but the selective advantages conferred are unknown. Here, the authors show that BACH2 and additionally STAT5B are activated by viral insertions, generating chimeric mRNAs specifically enriched in T regulatory cells favoring their persistence.
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Affiliation(s)
- Daniela Cesana
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy.
| | - Francesca R Santoni de Sio
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Laura Rudilosso
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Pierangela Gallina
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Andrea Calabria
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Stefano Beretta
- Department of Informatics, Systems and Communication, University of Milano-Bicocca, Viale Sarca 336, Milan, 20126, Italy.,National Research Council, Institute for Biomedical Technologies, Via Fratelli Cervi 93, Segrate, 20090, Italy
| | - Ivan Merelli
- National Research Council, Institute for Biomedical Technologies, Via Fratelli Cervi 93, Segrate, 20090, Italy
| | - Elena Bruzzesi
- Department of Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Laura Passerini
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Silvia Nozza
- Department of Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Elisa Vicenzi
- Viral Pathogens and Biosafety Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Guido Poli
- AIDS Immunopathogenesis Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy.,Vita-Salute San Raffaele University School of Medicine, Milan, 20132, Italy
| | - Silvia Gregori
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Giuseppe Tambussi
- Department of Infectious Diseases, IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy
| | - Eugenio Montini
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS, San Raffaele Scientific Institute, Milan, 20132, Italy.
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9
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Mullins JI, Frenkel LM. Clonal Expansion of Human Immunodeficiency Virus-Infected Cells and Human Immunodeficiency Virus Persistence During Antiretroviral Therapy. J Infect Dis 2017; 215:S119-S127. [PMID: 28520966 DOI: 10.1093/infdis/jiw636] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The latent HIV-1 reservoir in blood decays very slowly, even during prolonged suppression of viral replication by antiretroviral therapy (ART). Mechanisms for reservoir persistence include replenishment through low-level viral replication, longevity and homeostatic proliferation of memory T cells, and most recently appreciated, clonal expansion of HIV-infected cells. Clonally expanded cells make up a large and increasing fraction of the residual infected cell population on ART, and insertion of HIV proviruses into certain host cellular genes has been associated with this proliferation. That the vast majority of proviruses are defective clouds our assessment of the degree to which clonally expanded cells harbor infectious viruses, and thus the extent to which they contribute to reservoirs relevant to curing infection. This review summarizes past studies that have defined our current understanding and the gaps in our knowledge of the mechanisms by which proviral integration and clonal expansion sustain the HIV reservoir.
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Affiliation(s)
- James I Mullins
- Departments of Microbiology, Medicine, Global Health and Laboratory Medicine, University of Washington, Seattle, WA, US
| | - Lisa M Frenkel
- Departments of Pediatrics, Medicine, Global Health and Laboratory Medicine, University of Washington, Seattle, WA, US.,Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, US
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10
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Bifurcated BACH2 control coordinates mantle cell lymphoma survival and dispersal during hypoxia. Blood 2017; 130:763-776. [PMID: 28592433 DOI: 10.1182/blood-2017-02-767293] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 05/31/2017] [Indexed: 02/07/2023] Open
Abstract
BACH2, a B-cell-specific transcription factor, plays a critical role in oxidative stress-mediated drug resistance in mantle cell lymphoma (MCL); however, the biological functions of BACH2 and its regulation of B-cell malignancies in chronic hypoxic microenvironment have not been studied. Here, we found that silencing BACH2 led to not only increased tumor formation and colony formation but also increased tumor dispersal to spleen and bone marrow. Decreased BACH2 levels in patients were also correlated with bone marrow and gastrointestinal dispersal of MCL and blastoid subtypes of MCL. Unexpectedly, decreased BACH2 levels in dispersed MCL cells were due to direct transcriptional repression by hypoxia-induced factor 1α (HIF-1α) and increased heme-mediated protein degradation. In normoxic conditions, BACH2 was able to modulate HIF-1α degradation by suppressing prolyl hydroxylase 3 expression. Bifurcated BACH2 controls during hypoxia and normoxia coordinate not only MCL tumor dispersal but also drug resistance, including bortezomib resistance, via plasmacytic differentiation. Our data highlight an interactive relationship between tumor cells and local microenvironment and the mechanisms of B-cell transcription factor in the regulation of MCL dispersal.
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Varadarajan J, McWilliams MJ, Mott BT, Thomas CJ, Smith SJ, Hughes SH. Drug resistant integrase mutants cause aberrant HIV integrations. Retrovirology 2016; 13:71. [PMID: 27682062 PMCID: PMC5041404 DOI: 10.1186/s12977-016-0305-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 09/19/2016] [Indexed: 12/21/2022] Open
Abstract
Background
HIV-1 integrase is the target for three FDA-approved drugs, raltegravir, elvitegravir, and dolutegravir. All three drugs bind at the active site of integrase and block the strand transfer step of integration. We previously showed that sub-optimal doses of the anti-HIV drug raltegravir can cause aberrant HIV integrations that are accompanied by a variety of deletions, duplications, insertions and inversions of the adjacent host sequences. Results We show here that a second drug, elvitegravir, also causes similar aberrant integrations. More importantly, we show that at least two of the three clinically relevant drug resistant integrase mutants we tested, N155H and G140S/Q148H, which reduce the enzymatic activity of integrase, can cause the same sorts of aberrant integrations, even in the absence of drugs. In addition, these drug resistant mutants have an elevated IC50 for anti-integrase drugs, and concentrations of the drugs that would be optimal against the WT virus are suboptimal for the mutants. Conclusions We previously showed that suboptimal doses of a drug that binds to the HIV enzyme integrase and blocks the integration of a DNA copy of the viral genome into host DNA can cause aberrant integrations that involve rearrangements of the host DNA. We show here that suboptimal doses of a second anti-integrase drug can cause similar aberrant integrations. We also show that drug-resistance mutations in HIV integrase can also cause aberrant integrations, even in the absence of an anti-integrase drug. HIV DNA integrations in the oncogenes BACH2 and MKL2 that do not involve rearrangements of the viral or host DNA can stimulate the proliferation of infected cells. Based on what is known about the association of DNA rearrangements and the activation of oncogenes in human tumors, it is possible that some of the deletions, duplications, insertions, and inversions of the host DNA that accompany aberrant HIV DNA integrations could increase the chances that HIV integrations could lead to the development of a tumor. Electronic supplementary material The online version of this article (doi:10.1186/s12977-016-0305-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Janani Varadarajan
- HIV Dynamics and Replication Program, Vector Design and Replication Section, National Cancer Institute-Frederick, 1050 Boyles Street, Bldg. 539, Room 130A, Frederick, MD, 21702, USA.,Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Mary Jane McWilliams
- HIV Dynamics and Replication Program, Vector Design and Replication Section, National Cancer Institute-Frederick, 1050 Boyles Street, Bldg. 539, Room 130A, Frederick, MD, 21702, USA
| | - Bryan T Mott
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, USA
| | - Craig J Thomas
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, USA
| | - Steven J Smith
- HIV Dynamics and Replication Program, Vector Design and Replication Section, National Cancer Institute-Frederick, 1050 Boyles Street, Bldg. 539, Room 130A, Frederick, MD, 21702, USA
| | - Stephen H Hughes
- HIV Dynamics and Replication Program, Vector Design and Replication Section, National Cancer Institute-Frederick, 1050 Boyles Street, Bldg. 539, Room 130A, Frederick, MD, 21702, USA.
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Zhang WW, Sun XF, Tong HL, Wang YH, Li SF, Yan YQ, Li GP. Effect of differentiation on microRNA expression in bovine skeletal muscle satellite cells by deep sequencing. Cell Mol Biol Lett 2016; 21:8. [PMID: 28536611 PMCID: PMC5415838 DOI: 10.1186/s11658-016-0009-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 09/25/2015] [Indexed: 01/01/2023] Open
Abstract
Background The differentiation of skeletal muscle-derived satellite cells (MDSCs) is important in controlling muscle growth, improving livestock muscle quality, and healing of muscle-related disease. MicroRNAs (miRNAs) are a class of gene expression regulatory factors, which play critical roles in the regulation of muscle cell differentiation. This study aimed to compare the expression profile of miRNAs in MDSC differentiation, and to investigate the miRNAs which are involved in MDSC differentiation. Method Total RNA was extracted from MDSCs at three different stages of differentiation (MDSC-P, MDSC-D1 and MDSC-D3, representing 0, 1 and 3 days after differentiation, respectively), and used to construct small RNA libraries for RNA sequencing (RNA-seq). Results The results showed that in total 617 miRNAs, including 53 novel miRNA candidates, were identified. There were 9 up-expressed, 165 down-expressed, and 15 up-expressed, 145 down-expressed in MDSC-D1 and MDSC-D3, respectively, compared to those in MDSC-P. Also, 17 up-expressed, 55 down-expressed miRNAs were observed in MDSC-D3 compared to those in MDSC-D1. All known miRNAs belong to 237 miRNA gene families. Furthermore, we observed some sequence variants and base edits of the miRNAs. GO and KEGG pathway analysis showed that the majority of target genes regulated by miRNAs were involved in cellular metabolism, pathways in cancer, actin cytoskeleton regulation and the MAPK signaling pathway. Regarding the 53 novel miRNAs, there were 7 up-expressed, 31 down-expressed, and 8 up-expressed, 26 down-expressed in MDSC-D1 and MDSC-D3, respectively, compared to those in MDSC-P. The expression levels of 12 selected miRNA genes detected by RT-qPCR were consistent with those generated by deep sequencing. Conclusions This study confirmed the authenticity of 564 known miRNAs and identified 53 novel miRNAs which were involved in MDSC differentiation. The identification of novel miRNAs has significantly expanded the repertoire of bovine miRNAs and could contribute to advances in understanding muscle development in cattle. Electronic supplementary material The online version of this article (doi:10.1186/s11658-016-0009-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wei Wei Zhang
- The Laboratory of Cell and Development, Northeast Agricultural University, Mucai Street 59, Xiangfang District, Harbin, 150030 Heilongjiang China.,College of Life Sciences and Agriculture & Forestry, Qiqihar University, Qiqihar, Heilongjiang 161006 China
| | - Xiao Feng Sun
- The Laboratory of Cell and Development, Northeast Agricultural University, Mucai Street 59, Xiangfang District, Harbin, 150030 Heilongjiang China
| | - Hui Li Tong
- The Laboratory of Cell and Development, Northeast Agricultural University, Mucai Street 59, Xiangfang District, Harbin, 150030 Heilongjiang China
| | - Ya Hui Wang
- The Laboratory of Cell and Development, Northeast Agricultural University, Mucai Street 59, Xiangfang District, Harbin, 150030 Heilongjiang China
| | - Shu Feng Li
- The Laboratory of Cell and Development, Northeast Agricultural University, Mucai Street 59, Xiangfang District, Harbin, 150030 Heilongjiang China
| | - Yun Qin Yan
- The Laboratory of Cell and Development, Northeast Agricultural University, Mucai Street 59, Xiangfang District, Harbin, 150030 Heilongjiang China
| | - Guang Peng Li
- The Key Laboratory of Mammal Reproductive Biology and Biotechnology Ministry of Education, Inner Mongolia University, Hohhot, 010021 China
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Maldarelli F. The role of HIV integration in viral persistence: no more whistling past the proviral graveyard. J Clin Invest 2016; 126:438-47. [PMID: 26829624 DOI: 10.1172/jci80564] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A substantial research effort has been directed to identifying strategies to eradicate or control HIV infection without a requirement for combination antiretroviral therapy (cART). A number of obstacles prevent HIV eradication, including low-level viral persistence during cART, long-term persistence of HIV-infected cells, and latent infection of resting CD4+ T cells. Mechanisms of persistence remain uncertain, but integration of the provirus into the host genome represents a central event in replication and pathogenesis of all retroviruses, including HIV. Analysis of HIV proviruses in CD4+ lymphocytes from individuals after prolonged cART revealed that a substantial proportion of the infected cells that persist have undergone clonal expansion and frequently have proviruses integrated in genes associated with regulation of cell growth. These data suggest that integration may influence persistence and clonal expansion of HIV-infected cells after cART is introduced, and these processes may represent key mechanisms for HIV persistence. Determining the diversity of host genes with integrants in HIV-infected cells that persist for prolonged periods may yield useful information regarding pathways by which infected cells persist for prolonged periods. Moreover, many integrants are defective, and new studies are required to characterize the role of clonal expansion in the persistence of replication-competent HIV.
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14
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Wagner TA, McLaughlin S, Garg K, Cheung CYK, Larsen BB, Styrchak S, Huang HC, Edlefsen PT, Mullins JI, Frenkel LM. HIV latency. Proliferation of cells with HIV integrated into cancer genes contributes to persistent infection. Science 2014; 345:570-3. [PMID: 25011556 DOI: 10.1126/science.1256304] [Citation(s) in RCA: 509] [Impact Index Per Article: 50.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Antiretroviral treatment (ART) of HIV infection suppresses viral replication. Yet if ART is stopped, virus reemerges because of the persistence of infected cells. We evaluated the contribution of infected-cell proliferation and sites of proviral integration to HIV persistence. A total of 534 HIV integration sites (IS) and 63 adjacent HIV env sequences were derived from three study participants over 11.3 to 12.7 years of ART. Each participant had identical viral sequences integrated at the same position in multiple cells, demonstrating infected-cell proliferation. Integrations were overrepresented in genes associated with cancer and favored in 12 genes across multiple participants. Over time on ART, a greater proportion of persisting proviruses were in proliferating cells. HIV integration into specific genes may promote proliferation of HIV-infected cells, slowing viral decay during ART.
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Affiliation(s)
- Thor A Wagner
- Seattle Children's Research Institute, 1900 9th Avenue, Seattle, WA 98101, USA. University of Washington, Seattle, WA, USA
| | - Sherry McLaughlin
- Seattle Children's Research Institute, 1900 9th Avenue, Seattle, WA 98101, USA. University of Washington, Seattle, WA, USA
| | - Kavita Garg
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | | | - Sheila Styrchak
- Seattle Children's Research Institute, 1900 9th Avenue, Seattle, WA 98101, USA
| | - Hannah C Huang
- Seattle Children's Research Institute, 1900 9th Avenue, Seattle, WA 98101, USA
| | - Paul T Edlefsen
- University of Washington, Seattle, WA, USA. Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | - Lisa M Frenkel
- Seattle Children's Research Institute, 1900 9th Avenue, Seattle, WA 98101, USA. University of Washington, Seattle, WA, USA.
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15
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Maldarelli F, Wu X, Su L, Simonetti FR, Shao W, Hill S, Spindler J, Ferris AL, Mellors JW, Kearney MF, Coffin JM, Hughes SH. HIV latency. Specific HIV integration sites are linked to clonal expansion and persistence of infected cells. Science 2014; 345:179-83. [PMID: 24968937 DOI: 10.1126/science.1254194] [Citation(s) in RCA: 637] [Impact Index Per Article: 63.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The persistence of HIV-infected cells in individuals on suppressive combination antiretroviral therapy (cART) presents a major barrier for curing HIV infections. HIV integrates its DNA into many sites in the host genome; we identified 2410 integration sites in peripheral blood lymphocytes of five infected individuals on cART. About 40% of the integrations were in clonally expanded cells. Approximately 50% of the infected cells in one patient were from a single clone, and some clones persisted for many years. There were multiple independent integrations in several genes, including MKL2 and BACH2; many of these integrations were in clonally expanded cells. Our findings show that HIV integration sites can play a critical role in expansion and persistence of HIV-infected cells.
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Affiliation(s)
- F Maldarelli
- HIV Drug Resistance Program, National Cancer Institute, Frederick, MD 21702, USA
| | - X Wu
- Leidos Biomedical Research, Frederick, MD 21702, USA
| | - L Su
- Leidos Biomedical Research, Frederick, MD 21702, USA
| | - F R Simonetti
- HIV Drug Resistance Program, National Cancer Institute, Frederick, MD 21702, USA. Department of Biomedical and Clinical Sciences L. Sacco, University of Milan, 20122 Milan, Italy
| | - W Shao
- Leidos Biomedical Research, Frederick, MD 21702, USA
| | - S Hill
- HIV Drug Resistance Program, National Cancer Institute, Frederick, MD 21702, USA
| | - J Spindler
- HIV Drug Resistance Program, National Cancer Institute, Frederick, MD 21702, USA
| | - A L Ferris
- HIV Drug Resistance Program, National Cancer Institute, Frederick, MD 21702, USA
| | - J W Mellors
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - M F Kearney
- HIV Drug Resistance Program, National Cancer Institute, Frederick, MD 21702, USA
| | - J M Coffin
- Department of Molecular Biology and Microbiology, Tufts University, Boston, MA 02111, USA
| | - S H Hughes
- HIV Drug Resistance Program, National Cancer Institute, Frederick, MD 21702, USA.
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16
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Swaminathan S, Duy C, Müschen M. BACH2-BCL6 balance regulates selection at the pre-B cell receptor checkpoint. Trends Immunol 2014; 35:131-7. [PMID: 24332591 PMCID: PMC3943645 DOI: 10.1016/j.it.2013.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 09/16/2013] [Accepted: 11/10/2013] [Indexed: 11/21/2022]
Abstract
At the pre-B cell receptor (BCR) checkpoint, developing pre-B cells are selected for successful rearrangement of V(H)-DJ(H) gene segments and expression of a pre-BCR. Reduced stringency at this checkpoint may obstruct the B cell repertoire with nonfunctional B cell clones. Earlier studies have described that activation of B cell lymphoma/leukemia (BCL)6 by a functional pre-BCR mediates positive selection of pre-B cells that have passed the checkpoint. This concept is now further elaborated by the recent finding that the BTB and CNC homology 1 basic leucine zipper transcription factor 2 (BACH2) induces negative selection and opposes BCL6 function prior to the pre-BCR checkpoint. Here, we discuss the antagonism between BCL6 and BACH2 during early B cell development, as well as its implications in both repertoire selection and counter-selection of premalignant clones for leukemia suppression.
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Affiliation(s)
- Srividya Swaminathan
- Department of Laboratory Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Cihangir Duy
- Departments of Medicine and Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA
| | - Markus Müschen
- Department of Laboratory Medicine, University of California San Francisco, San Francisco, CA 94143, USA.
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Deregulated Nras expression in knock-in animals harboring a gammaretroviral long terminal repeat at the Nras/Csde1 locus. PLoS One 2013; 8:e56029. [PMID: 23418499 PMCID: PMC3572152 DOI: 10.1371/journal.pone.0056029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 01/04/2013] [Indexed: 12/01/2022] Open
Abstract
To investigate mechanisms and phenotypic effects of insertional mutagenesis by gammaretroviruses, we have developed mouse lines containing a single Akv 1-99 long terminal repeat (LTR) and a floxed PGK/Tn5 neomycin cassette at the Nras proto-oncogene at positions previously identified as viral integration sites in Akv 1-99 induced tumors. The insert did not compromise the embryonic development, however, the cassette had an effect on Nras expression in all tissues analyzed. Cre-mediated excision of the PGK/Tn5 neomycin cassette in two of the lines caused upregulation of Nras. Altogether, the knock-in alleles are characterized by modulation of expression of the target gene from more than ten-fold upregulation to three-fold downregulation and exemplify various mechanisms of deregulation by insertional mutagenesis. LTR knock-in mice may serve as a tool to investigate mechanisms of retroviral insertional mutagenesis and as a way of constitutive or induced modulation of expression of a target gene.
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18
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Türkmen S, Riehn M, Klopocki E, Molkentin M, Reinhardt R, Burmeister T. A BACH2-BCL2L1 fusion gene resulting from a t(6;20)(q15;q11.2) chromosomal translocation in the lymphoma cell line BLUE-1. Genes Chromosomes Cancer 2011; 50:389-96. [PMID: 21412927 DOI: 10.1002/gcc.20863] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2010] [Accepted: 01/27/2011] [Indexed: 11/06/2022] Open
Abstract
Abnormalities of the long arm of chromosome 6 are a common feature in various B-cell malignancies. In most cases, the genes involved have not yet been clearly identified. We have molecularly characterized the recently established Burkitt lymphoma cell line BLUE-1 that carries a t(6;20)(q15;q11.2) rearrangement in addition to the typical t(8;14) with MYC-IGH fusion. To identify the gene loci involved on both chromosomes we applied a sequential BAC clone mapping strategy. By using RT-PCR we were finally able to detect a chimeric mRNA transcript showing a fusion of the first (non-coding) exon of BACH2 (BTB and CNC homology 1, basic leucine zipper transcription factor 2) on 6q15 to the second exon of BCL2L1 (BCL-X) on 20q11. Various fusion transcripts were detected for different BCL2L1 (BCL-XL) isoforms. The fusion ultimately results in strong expression of the BCL2L1 (BCL-XL) anti-apoptosis protein, as demonstrated by immunoblotting. This is the first report that shows the involvement of both BCL2L1 and the transcription factor BACH2 in a chromosomal rearrangement. It points to BACH2 as a possibly important target in lymphomas with 6q aberrations, although other genes on 6q are probably also involved in these cases. Moreover, it suggests that members of the BCL2 anti-apoptosis gene family other than BCL2 itself might also be involved in lymphoma.
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Affiliation(s)
- Seval Türkmen
- Institut für Medizinische Genetik, Charité CVK, Berlin, Germany
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Pyrz M, Wang B, Wabl M, Pedersen FS. A retroviral mutagenesis screen identifies Cd74 as a common insertion site in murine B-lymphomas and reveals the existence of a novel IFNgamma-inducible Cd74 isoform. Mol Cancer 2010; 9:86. [PMID: 20416035 PMCID: PMC2883540 DOI: 10.1186/1476-4598-9-86] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 04/23/2010] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Insertional mutagenesis screens in the mouse are an acknowledged approach to identify genes involved in the pathogenesis of cancer. The potential of these screens to identify genes causally involved in tumorigenesis is not only limited to the murine host, but many of these genes have also been proven to be involved in the oncogenic process in man. RESULTS Through an insertional mutagenesis screen applying murine leukemia viruses in mouse, we found that Cd74 was targeted by proviral insertion in tumors of B-cell origin. This locus encodes a protein playing crucial roles in antigen presentation and B-cell homeostasis, and its deregulation is often associated with cancer in man. The distribution of insertions within the Cd74 locus prompted the identification of an alternative transcript initiated in intron 1 of Cd74 encoding an N-terminally truncated Cd74 isoform in tissues from un-infected mice, and transcriptional activation assays revealed a positive effect on the novel intronic promoter by a formerly described intronic enhancer in the Cd74 locus. Furthermore, we show that the new Cd74 isoform is IFNgamma inducible and that its expression is differentially regulated from the canonical Cd74 isoform at the transcriptional level. CONCLUSIONS We here identify Cd74 as a common insertion site in murine B-lymphomas and describe a novel IFNgamma-inducible murine Cd74 isoform differentially regulated from the canonical isoform and expressed under the control of an intronic promoter. The distribution and orientation of proviral insertion sites within the Cd74 locus underscores the causal involvement of the isoforms in the murine B-lymphomagenic process.
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Affiliation(s)
- Magdalena Pyrz
- Department of Molecular Biology, Aarhus University, Aarhus, DK-8000, Denmark
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Antisense transcription in gammaretroviruses as a mechanism of insertional activation of host genes. J Virol 2010; 84:3780-8. [PMID: 20130045 DOI: 10.1128/jvi.02088-09] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transcription of retroviruses is initiated at the U3-R region boundary in the integrated provirus and continues unidirectionally to produce genomic and mRNA products of positive polarity. Several studies have recently demonstrated the existence of naturally occurring protein-encoding transcripts of negative polarity in complex retroviruses. We report here on the identification of transcripts of negative polarity in simple murine leukemia virus (MLV). In T-cell and B-cell lymphomas induced by SL3-3 and Akv MLV, antisense transcripts initiated in the U3 region of the proviral 5' long terminal repeat (LTR) and continued into the cellular proto-oncogenes Jdp2 and Bach2 to create chimeric transcripts consisting of viral and host sequence. The phenomenon was validated in vivo using a knock-in mouse model homozygous for a single LTR at a position known to activate Nras in B-cell lymphomas. A 5' rapid amplification of cDNA ends (RACE) analysis indicated a broad spectrum of initiation sites within the U3 region of the 5' LTR. Our data show for the first time transcriptional activity of negative polarity initiating in the U3 region of simple retroviruses and suggest a novel mechanism of insertional activation of host genes. Elucidation of the nature and potential regulatory role of 5' LTR antisense transcription will be relevant to the design of therapeutic vectors and may contribute to the increasing recognition of pervasive eukaryotic transcription.
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Rasmussen MH, Wang B, Wabl M, Nielsen AL, Pedersen FS. Activation of alternative Jdp2 promoters and functional protein isoforms in T-cell lymphomas by retroviral insertion mutagenesis. Nucleic Acids Res 2009; 37:4657-71. [PMID: 19502497 PMCID: PMC2724284 DOI: 10.1093/nar/gkp469] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Retroviral insertional mutagenesis has been instrumental for the identification of genes important in cancer development. The molecular mechanisms involved in retroviral-mediated activation of proto-oncogenes influence the distribution of insertions within specific regions during tumorigenesis and hence may point to novel gene structures. From a retroviral tagging screen on tumors of 1767 SL3-3 MLV-infected BALB/c mice, intron 2 of the AP-1 repressor Jdp2 locus was found frequently targeted by proviruses resulting in upregulation of non-canonical RNA subspecies. We identified several promoter regions within 1000 bp upstream of exon 3 that allowed for the production of Jdp2 protein isoforms lacking the histone acetylase inhibitory domain INHAT present in canonical Jdp2. The novel Jdp2 isoforms localized to the nucleus and over-expression in murine fibroblast cells induced cell death similar to canonic Jdp2. When expressed in the context of oncogenic NRAS both full length Jdp2 and the shorter isoforms increased anchorage-independent growth. Our results demonstrate a biological function of Jdp2 lacking the INHAT domain and suggest a post-genomic application for the use of retroviral tagging data in identifying new gene products with a potential role in tumorigenesis.
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